Scalpel from Bank

Here is the Scalpel Building, seen from Bank Junction.

The statue in the centre of the bottom of the picture is neither a statesman, nor a warrior, nor a monarch. It celebrates an engineer: J.H. Greathead, “inventor of the travelling shield that made possible the cutting of the tunnels of London’s deep level tube system”. There is a picture of his invention on the plinth.

The “travelling shield” depicted on the plinth of Greathead’s statue in Cornhill.

Greathead’s idea was to make the shield cylindrical, rather than rectangular as it had been previously. He also invented ways to spray concrete and grouting on the walls, and also to pressurise the tunnel, so as to make the workers a bit safer from cave-ins. His later shields were equipped with cutting jaws or teeth, to excavate the earth ahead.

“Most tunnelling shields are still loosely based on Greathead’s Shields design” says Wikipedia, including the “Tunnel Boring Machines” which are used, for example, for Crossrail.

The statue was created in 1994, and stands, appropriately enough, on a ventilation shaft for the Waterloo and City Line.

J.H. Greathead on his plinth/ventilation shaft.

I drew this picture standing at One Poultry. Here are maps:

Here is work in progress:

Work in progress, the scene from One Poultry.

About 45 minutes. The sky is Prussian Blue, very dilute. The other colours used are Mars Yellow, and Perylene Maroon, all Daniel Smith watercolours. The grey is Perylene Maroon and Prussian Blue. The traffic lights are Pyrrol Red.

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